The present invention generally relates to security systems, and more particularly to a vehicle security arrangement.
From, German Patent No. 43 25 657 describing a theft prevention mechanism for vehicles brought about by specifically blocking assemblies critical to operation. Action modules handle the disabling or enabling of the respectively assigned modules. A code stored on a code key is detected by a code reader and forwarded to all action modules. A logic unit of the action module compares the code with information stored in the code memory of the action module. If both do not agree, the action module deactivates the associated functional assembly. It is also provided that in case of a mismatch, the action module can bring about the destruction of the relevant assembly. Data transmission and data comparison in the action modules are triggered by introducing the code key into the code reader.
The present invention provides a vehicle security arrangement that realizes increased theft protection.
According to the present invention, improved theft protection is achieved in that the enabling of each functional control unit takes place as a function of a comparison of two code words. The first code word is provided by the respective functional control unit and the second code word is provided by an input unit. The theft protection control unit initiates the provision of both code words. By incorporating multiple functional control units relevant to travel operation, the security against unauthorized start-up of the vehicle is further increased. Each functional control unit checks for itself whether an authorized user is accessing the vehicle. This renders it more difficult, in particular, to exchange functional control units with units coming, e.g., from stolen vehicles, since the functional control units must be matched to the theft protection control unit and also to the input unit. If this is not the case, then the functional control unit denies its usage. The control of the enabling procedure by the theft protection control unit increases the security against monitoring by influencing code words in a randomly controlled manner. The theft protection control unit affects a precise preselection which gets the authorization of the possibly multiple input units to provide the second code word.
The present invention further provides that a forwarding of the second code word, which is provided by the input unit, to the functional control unit takes place if the second code word matches the code word expected by the theft protection control unit. A further authorization query performed in the theft protection control unit increases the theft protection. The measure also increases the convenience, for instance, if due to transmission error(s) the second code word arrives garbled at the theft protection control unit. This can trigger a request to the input unit to repeat the transmission or provision procedure of the second code word without the incorrect second code word already having led to a malfunction of the functional control units.
The present invention may also provide an authorization algorithm or keyword or both assisting in the generation of the first and the second code words. Particularly with a vehicle-specific keyword, the authorization algorithm can be chosen the same for each vehicle. This separation ensures on the one hand that an individual code word is assigned to each vehicle. On the other hand, it is guaranteed for the manufacturer that by using one and the same authorization algorithm for each vehicle, a high degree of standardization is achieved, which becomes noticeable in terms of decreased costs in the manufacturing process.
The present invention may also provide that to generate the first and second code words, a third code word is used whose provision takes place through the theft protection control unit. Protection against monitoring can be realized in this manner by drawing upon, for example, another third code word, randomly controlled, for each initiation procedure. Constant communication procedures are thus avoided, thereby decreasing the risk of transferring the vehicle through intentional manipulation into a driveable state.
The present invention may also provide that the initiation of the theft protection control unit occurs after actuating a switch. The coupling of the enabling process, e.g., with an ignition lock, increases the security by also taking into account conventional locking devices.
The present invention may also provide, for example, transponders and/or electronic chip cards input units. The transponder increases the convenience through wireless communication with the theft protection control unit. The electronic chip card is advantageous in that the mechanical accessibility of the read unit can be made more difficult through additional control mechanisms, which further enhances security.
The present invention may also provide a master input unit containing the keyword. This master input unit is required if functional control units or input units are to be exchanged. The exchange of vehicle-specific modules in stolen vehicles is made considerably more difficult in this manner.
The present invention may also provide a technique for parametrizing a vehicle security arrangement, the functional control unit and theft protection control unit being operated in a parametrizing mode. An additional device informs the functional control unit and the theft protection control unit of the vehicle-specific keyword which is then forwarded on the part of the theft protection control unit to the input device. This procedure enables a favorable parametrizing process from a manufacturing-engineering viewpoint at the end of the assembly line.